Performa 5200 & Beige G3 300MHz: Worked out of the box as far as I can remember. The G3 is still working, the Performa's screen died a few years ago
G3 iMac (slot loading): Worked fine out of the box and haven't had a problem since
G3 iBook: Again, worked fine out of the box. The battery can only last about 30mins now from full charge, browsing the internet with IE on OS9.2.1
Dual 867MHz G4: Worked fine out of the box, but Photoshop 5 + Dual processors + OS9 = corrupted HD. Within about 3 months, we had to reformat. Recently, we put a second HD in (160Gb), maxed out the RAM and installed Tiger (best move yet
) - it runs better than it ever did
G4 PowerBook 1.5GHz (August 2005 model): Worked fine out of the box, despite the Apple Store not installing the extra RAM we ordered. After a couple of hours of haggling with the store manager (we were about 2 hours drive and a £2 toll away from the store, and didn't fancy driving the PB back down there to get the extra RAM installed), an Apple Tech came to our house and installed the chip of RAM. It's worked great ever since
Only problem is the battery doesn't do that good a job of holding its charge...